#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>

void d0_ls(char[]);
void dostat(char *);
void show_file_info(char *,struct stat *);
void mode_to_lettrs(int ,char []);
char *uid_to_name(uid_t);
char *gid_to_name(gid_t);

int main(int argc,char *argv[])
{
if(argc == 1)
do_ls(".");
else
while(--argc)
{
printf("%s:\n",*++argv);
do_ls(*argv);
}
return 0;
}
void do_ls(char dirname[])
{
DIR *dir_ptr;
struct dirent *direntp;

if((dir_ptr = opendir(dirname)) == NULL)
fprintf(stderr,"ls1 cannot open %s\n",dirname);
else
{
while ((direntp = readdir(dir_ptr)) != NULL)
dostat(direntp->d_name);
closedir(dir_ptr);
}
}

void dostat(char *filename)
{
struct stat info;

if(stat(filename,&info)==-1)
perror(filename);
else
show_file_info(filename,&info);
}

void show_file_info(char *filename,struct stat *info_p)
{
char *uid_to_name(),*ctime(),*gid_to_name(),*filemode();
void mode_to_letters();
char modestr[11];

mode_to_letters(info_p->st_mode,modestr);

printf("%s",modestr);
printf("%4d",(int)info_p->st_nlink);
printf("%-8s",uid_to_name(info_p->st_uid));
printf("%-8s",gid_to_name(info_p->st_gid));
printf("8ld",(long)info_p->st_size);
printf("%.12s",4+ctime(&info_p->st_mtime));
printf("%s\n",filename);
}
void mode_to_letters(int mode,char str[])
{
strcpy(str,"----------");

if(S_ISDIR(mode)) str[0] ='d';
if(S_ISCHR(mode)) str[0] = 'c';
if(S_ISBLK(mode)) str[0] ='b';

if(mode & S_IRUSR) str[1] = 'r';
if(mode & S_IWUSR) str[2] = 'W';
if(mode & S_IXUSR) str[3] = 'x';

if(mode & S_IRGRP) str[4] = 'r';
if(mode & S_IWGRP) str[5] = "w";
if(mode & S_IXGRP) str[6] = "x";

if(mode & S_IROTH) str[7] = 'r';
if(mode & S_IWOTH) str[8] = 'w';
if(mode & S_IXOTH) str[9] = 'x';
}

#include <pwd.h>

char *uid_to_name(uid_t uid)
{
struct passwd *getpwuid(),*pw_ptr;
static char numstr[10];

if((pw_ptr = getpwuid(uid)) == NULL)
{
sprintf(numstr,"%d",uid);
return numstr;
}
else
return pw_ptr->pw_name;
}

#include <grp.h>

char *gid_to_name(gid_t gid)
{
struct group *getgrgid(),*grp_ptr;
static char numstr[10];

if((grp_ptr = getgrgid(gid)) ==NULL)
{
sprintf(numstr,"%d",gid);
return numstr;
}
else
return grp_ptr->gr_name;
}

